Free end drop for measuring flow rate in striped sides triangular channels

Free end water drop in striped sides triangular channels has been used as a tool for measuring end depth flow rate with its practical applications in triangular trenches. The current study’s laboratory work includes testing twelve channel models with striped sides in which strips have 1 cm x 1 cm square cross sections arranged in seven patterns of strips concentrations h s /L s ranging from 1/128 to 1/2 for various side slopes Z T and channel slopes S T . Five hundred fifty-four experiments are performed on the channel models covering a wide range of Froude numbers. It is important to note that roughness coefficient n T achieves its maximum value at strips concentration = 1/8 across all channel slopes. Curves of the end drop discharge (EDD) are presented for varied channel’s side slopes and bed slopes at h s /L s = 1/8. Ratio of end drop water depth D e to critical depth D c (EDR) demonstrated straight line correlations. D e /D c grows as h s /L s decreases, reaching a maximum value at h s /L s = 1/8. Variations of D e with uniform depth D n yielded straight line connections. A quadratic equation was found to exist between D e /D c and S T /n T with determination coefficient R 2 = 0.997. An empirical correlation for the fluctuation of dimensionless discharge in terms of D e /D c and S T /n T is obtained for different channel side slopes, channel bed slopes, h s /L s = 1/8, and a Froude number range of 0.39 to 0.87. Two empirical approaches are proposed for predicting flow rate in striped sides triangular channels.